@charset "utf-8";
.backtop{
  display: none;
  opacity: 0;
  width: 50px;
  height: 50px;
  position: fixed;
  right: 50px;
  bottom: 80px;
  border-radius: 5px;
  background: rgba(0,0,0,0.7);
  cursor: pointer;
  display: flex;
  justify-content: center;
  align-items: center;
  .icon-top{
    font-size: 30px;
    color: #fff;
  }
}
.show_backtop_btn{
  display: flex;
  opacity: 1;
}